Digital electronic circuits are known from the market, in particular digital integrated circuits, which result in a change of an operating current which is impulse-like in most cases in the case of internal switching operations of memory elements, e.g., of bistable multivibrators, so-called flip-flops. These changes in the operating current may be measured outside of the integrated circuit, thus making it possible to infer a particular data content of the memory elements with the aid of methods and algorithms which are already known. This is generally not desirable.